1/*
2 * Copyright (C) 2013, 2014 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27#include "DFGSSALoweringPhase.h"
28
29#if ENABLE(DFG_JIT)
30
31#include "DFGBasicBlockInlines.h"
32#include "DFGGraph.h"
33#include "DFGInsertionSet.h"
34#include "DFGPhase.h"
35#include "JSCInlines.h"
36
37namespace JSC { namespace DFG {
38
39class SSALoweringPhase : public Phase {
40    static const bool verbose = false;
41
42public:
43    SSALoweringPhase(Graph& graph)
44        : Phase(graph, "SSA lowering")
45        , m_insertionSet(graph)
46    {
47    }
48
49    bool run()
50    {
51        RELEASE_ASSERT(m_graph.m_form == SSA);
52
53        for (BlockIndex blockIndex = m_graph.numBlocks(); blockIndex--;) {
54            m_block = m_graph.block(blockIndex);
55            if (!m_block)
56                continue;
57            for (m_nodeIndex = 0; m_nodeIndex < m_block->size(); ++m_nodeIndex) {
58                m_node = m_block->at(m_nodeIndex);
59                handleNode();
60            }
61            m_insertionSet.execute(m_block);
62        }
63
64        return true;
65    }
66
67private:
68    void handleNode()
69    {
70        switch (m_node->op()) {
71        case GetByVal:
72            lowerBoundsCheck(m_node->child1(), m_node->child2(), m_node->child3());
73            break;
74
75        case PutByVal:
76        case PutByValDirect: {
77            Edge base = m_graph.varArgChild(m_node, 0);
78            Edge index = m_graph.varArgChild(m_node, 1);
79            Edge storage = m_graph.varArgChild(m_node, 3);
80            if (lowerBoundsCheck(base, index, storage))
81                break;
82
83            if (m_node->arrayMode().typedArrayType() != NotTypedArray && m_node->arrayMode().isOutOfBounds()) {
84                Node* length = m_insertionSet.insertNode(
85                    m_nodeIndex, SpecInt32, GetArrayLength, m_node->origin,
86                    OpInfo(m_node->arrayMode().asWord()), base, storage);
87
88                m_graph.varArgChild(m_node, 4) = Edge(length, KnownInt32Use);
89                break;
90            }
91            break;
92        }
93
94        default:
95            break;
96        }
97    }
98
99    bool lowerBoundsCheck(Edge base, Edge index, Edge storage)
100    {
101        if (!m_node->arrayMode().permitsBoundsCheckLowering())
102            return false;
103
104        if (!m_node->arrayMode().lengthNeedsStorage())
105            storage = Edge();
106
107        Node* length = m_insertionSet.insertNode(
108            m_nodeIndex, SpecInt32, GetArrayLength, m_node->origin,
109            OpInfo(m_node->arrayMode().asWord()), base, storage);
110        m_insertionSet.insertNode(
111            m_nodeIndex, SpecInt32, CheckInBounds, m_node->origin,
112            index, Edge(length, KnownInt32Use));
113        return true;
114    }
115
116    InsertionSet m_insertionSet;
117    BasicBlock* m_block;
118    unsigned m_nodeIndex;
119    Node* m_node;
120};
121
122bool performSSALowering(Graph& graph)
123{
124    SamplingRegion samplingRegion("DFG SSA Lowering Phase");
125    return runPhase<SSALoweringPhase>(graph);
126}
127
128} } // namespace JSC::DFG
129
130#endif // ENABLE(DFG_JIT)
131
132